Hydrocarbons are often produced from well bores by reciprocating downhole pumps that are driven from the surface by pumping units. A pumping unit is connected to its downhole pump by a rod string. Although several types of pumping units for reciprocating rod strings are known in the art, walking beam style pumps enjoy predominant use due to their simplicity and low maintenance requirements.
Each beam pump unit should be positioned so that the horsehead is properly positioned above the production tubing. This allows the bridle to travel vertically when raising and lowering the sucker rod. Not having a horsehead in this position can produce an offset force between the polish rod and the bridle, which may result in wear and increased friction between the polish rod and the stuffing box and tee. One possible consequence of this offset and friction is that the contents of the stuffing box may prematurely wear and deteriorate. If this occurs and the stuffing box is not timely repaired, a leak of the production fluid may develop, possibly causing an environmental hazard.
The alignment between the well bore and the beam pump is typically done at the time the well is completed and the beam pump is installed. Realignment may be necessary if the pump unit shifts or is serviced. One prior art method of performing this alignment involves hanging a plumb bob from the horsehead to find the location of the pump unit relative to the production tubing. This usually requires the bridle to be pulled away from the horsehead and the plumb bob string placed in the bridle groove or at another place on the horsehead above the center of the production tubing. An observer then sights the location of the plumb bob relative to the center of the production tubing.
Although widely adopted, the line suspending the plumb bob is subject to the vagaries of the weather; a small breeze may have the result of producing a misalignment between the horsehead and the center of the production tube. Additionally, the resting point of the plumb bob may be subjective to the eye and may not yield a true alignment if the bob is not unquestionably at a point resting immediately above the center of the polish rod. There is, therefore, a need for a cost-effective solution for aligning the pump unit with the wellhead that overcomes these and other deficiencies in the prior art.